code: def get_sym_by_name(name, sym_buffer):
      if name in sym_buffer:
          return sym_buffer[name]
      ret = None
      name_key = name[0:1]
      name_num = int(name[1:])
      # print('getting', name, name_key, name_num)
      if name_key == "C":
          assert name_num % 2 == 0
          bottom = get_sym_by_name("C%d" % (name_num // 2), sym_buffer)
          ret = conv_act_layer(
              bottom,
              "%s_C%d"(PREFIX, name_num),
              F1,
              kernel=(3, 3),
              pad=(1, 1),
              stride=(2, 2),
              act_type="relu",
              bias_wd_mult=_bwm,
          )
      elif name_key == "P":
          assert name_num % 2 == 0
          assert name_num <= max(config.RPN_FEAT_STRIDE)
          lateral = get_sym_by_name("L%d" % (name_num), sym_buffer)
          if name_num == max(config.RPN_FEAT_STRIDE) or name_num > 32:
              ret = mx.sym.identity(
                  lateral, name="%s_P%d" % (PREFIX, name_num)
              )
          else:
              bottom = get_sym_by_name(
                  "L%d" % (name_num * 2), sym_buffer
              )
              bottom_up = upsampling(
                  bottom, F1, "%s_U%d" % (PREFIX, name_num)
              )
              if config.USE_CROP:
                  bottom_up = mx.symbol.Crop(*[bottom_up, lateral])
              aggr = lateral + bottom_up
              aggr = conv_act_layer(
                  aggr,
                  "%s_A%d" % (PREFIX, name_num),
                  F1,
                  kernel=(3, 3),
                  pad=(1, 1),
                  stride=(1, 1),
                  act_type="relu",
                  bias_wd_mult=_bwm,
              )
              ret = mx.sym.identity(
                  aggr, name="%s_P%d" % (PREFIX, name_num)
              )
      elif name_key == "L":
          c = get_sym_by_name("C%d" % (name_num), sym_buffer)
          # print('L', name, F1)
          ret = conv_act_layer(
              c,
              "%s_L%d" % (PREFIX, name_num),
              F1,
              kernel=(1, 1),
              pad=(0, 0),
              stride=(1, 1),
              act_type="relu",
              bias_wd_mult=_bwm,
          )
      else:
          raise RuntimeError("%s is not a valid sym key name" % name)
      sym_buffer[name] = ret
      return ret
  
file_path: insightface/detection/retinaface/rcnn/symbol/symbol_common.py
imports: import mxnet
  import mxnet.ndarray
  import numpy
  from rcnn.config import config
  from rcnn.PY_OP import rpn_fpn_ohem3, cascade_refine
label_desc: Use image node_id 10 for calling a global function with example usage: get_sym_by_name(name, sym_buffer) and returns: ret, sym_buffer